DIED. John Cage, 79, idiosyncratic American composer; in New York City. An indifferent musician, but one of the century's seminal theoreticians, Cage wrote music for radios, blenders, flowerpots, whistles, cowbells, tape recorders and prepared pianos. "There is no noise," he once said, "only sound." The son of an inventor, the California-born Cage eventually settled in New York City, where he spent the last 50 years of his life, often in the company of his lifelong companion, the choreographer Merce Cunningham, for whom he wrote many pieces. Cage's free-ranging eclecticism influenced three generations of American composers, including Morton Feldman, Frederic Rzewski and Philip Glass.